Electrolyte for the manufacture of hydrogen peroxide



Patented June 7, 1932 1 ANTON KRATKIOFBRQOKLYN, NEW YonK, ASSIGNGR'TOJOHN'BENEdz-SONS,' coo! BROOKLYN, ,nnw yomr, A .CORPQBATION. or new Yong:

'ELEGTROLYTE "FOR jTI-IEMANUFACTURE'OFHYDROGEN ,PERGXIDE lie-Drawing. lpplication filed fl'une 12,

This invention relates: toprocesses of manufacture :of hydrogen peroxide and more par- 'ticularlyrefers. to improvements in solutions to be usedas electrolytes for'the production of anolyte liquor vfrom which the hydrogen peroxide is subsequently liberatedby distillation.

In the manufacture of hydrogen peroxide, the product is generally obtained'by the distillation of a solution containing among other ingredients persulphuricacid or a per- .sulphate, preferably, a persul phate of an alkali metal such as for instance, potassium. The distillation of such a solution, the other-ingredients of which are generally sulphu-ricfacid and Water, results in the liberation of hydrogen peroxide and water in (the form of steam, which areiled to ,a condenser where they are collected in the ,form o'fa solution of hydrogen peroxide in Water.

Processes now in use result in a relatively low yield of peroxideybecause-iof catalytic and other impuritiesuwhich are contained in the-mass and which cause an almost immediate dissociation of the peroxide .as'it is liberated, with loss of oxygen.

Hydrogen peroxide may either .be-obtai-ned bythe distillation of a solution of persulphuric acidin sulphuric acid and water, .or

else by the distillation of a solution lot-pertained, as against that of an electrolyte only composed of sulphuric acid diluted with water.

Theelectrolytic operation is conducted; in :the usua m nner :by passing a @current through the electrolyte v tram th ,anode to lu e cathodeflhe; container being divided e two chambers, an anodic chamber 'anda Ca- ,thedic chamber, by means of a rpor'ous ildiaphragm. The electrolysis of the mixture results i in the liberation of {hydrogen Qat the. cathode and-oxygen, at the ranode,fltlie hydrogen beinglost. and the oxygen being [recom- :bi.-ned with the sulphur ic acid ,or theibisulphate, or both, -,iforminga .persnlphuric acitl .or a gpersulphate. j o w 7 The reactions taking gplaceiin tithe vcourse .of the electrolytic operation areas .fQHO' If sulphuric-ac;donl-y andwater amused,

Athesame areeusedin the proportions o f:"80%

to v50% /,and-7.0% to 50% by -.v veight, .respecv ti vely, -.After approximately.txiiofhoursop- .eration,--the.- liquid the. catliodic chamberis practically unchanged, while ,the liquidjn thewanodic ,chamber or anolyte will hate acquired the composition of HA SQ 1+,H Q

that 2320; tpersu'lphuric acid) +1120 (-mater l gs a lbisulp ate alsois used-in -thecoinposi- ,tieni-ofan electrolyte, tor-instance; potassium isulphate KH Oi, etheksamei ezidded to J nixtureo-f .to Reso ate .70% to 50% 11 9, so as to prednce ,a rsatiltatedsoluw.tion this calls. for :an addition-05E gbetwepenea ;to.- parts. of th'e bisulphate,.to 100 parts :of

the lphuricacid-water solutiombyweight.

electrolyte will therefore lelti-ginally havethe composition After about two hours period during which the electric: current is caused *to electrolyze lyte will still bethe same, \yliilevthe ,anolyte will haye acquiredthe composition '--K S; 0 +H ;SO +H O,

the first named ingredient, ,potassiumflperisulplrate Representing ,about1 3(l% of. the 'SOlution by weight.

fl-he anolyte liquor !is -,subseguently disti -lled g,un' der; prope -conditions, giving occur- :lencejtotheliberation of HgQ i+ H O, ;.one of the atoms of oxygen going toiformrthe per- .oxide being. abstracted fromzthe persulphate which n then acguire erermunn seoe --ther;so'lution, the-composition .ofthe cathoof time.

It is obvious that the best operating conditions are obtained when the electrolyte is highly responsive to the action of the electric current and when separation ofthe catholyte from the anolyte due to the electrolyte action having occurred, the possibility of mutual'diffusion of the two bodies of liquid within each other through the porous diaphragm separating them, is impeded or y p previously mentioned In order to further eliminated. I

A high conductivity of the electrolyte results in the possibility, of usinglower voltages with consequent savings of electric current, and the retarding or impeding of diffusion results in a greater quantity of anolyte liquor being formed in a given period and similarly an anolyte containing a p'ersul- 'phate. has a greater containing only persulphuric acid.

viscosity than an anolyte It is therefore obvious'that due to the greater viscosity of the two bodies of liquid, the influence of the'diifusion factor will be lessened to a considerable extent.

The primary object of this invention is to provide a novel and'improved type of electrolyte adapted for use in the'preliminary stagesof a 'process'of' manufacture ofhydrogen peroxide, whereby a higher yield of perlsulphate is obtained than is obtainable by means of electrolytes heretofore" known, under the same conditions. 1

improved type of electrolyte adapted for the electrolytic production of a persulphate solution, having a relatively high conductivity and permitting the employment of relatively low voltages with consequent savings in power costs.

A still further object is to provide an improved electrolyte of a relatively inexpensive nature, which may be compounded from readily available ingredients and which does notrequire any special experience either for its preparation or its operation. I Other objects and advantages of the present invention will more fully appear as the description proceeds and will be set forth andof another alkali metal; similarly another claimed in the appended claims. v,

In compounding my improved electrolyte,

I take 150 parts of water by weight; and to these I-add "from 10' @0 60 parts of potas- V sium sulphate K SO. and from '5 to 40 parts the preferred proportions being H 0 150' "parts by weight, K SO parts, by weight,

o'fsulphuric acid, H SO commercial grade,

I add, from 5 to 70 parts of ammonium sulphate (NH SO the preferred proportion being parts.

An electrolyte of the above composition has a greater conductivity and results in a greater yield of per-sulphate than-an electrolyte of the ordinary composition KHSO; H SO H O improve the solution. I then add from to the preferred proportion being 5 parts.

To'the above, I can also finally add arelatively small proportion of cerium sulphate, Ce (SO;)3, namely to 10 parts, preferably about 3 parts by weight. I have found that the latter ingredient materially assists the electrolytic action, speeding up the electrolytic dissociation: and consequentlyspeeding up theformation of per-sulphates; but the addition should not be excessive because it might otherwise result in a pronounced catalytic effect during the subsequent process of distillation which might cause dissociation and consequent loss of oxygen.

3 The preferred type of solution should have substantially the following composition 2 Parts by weight WVa-ter 1'50 Potassium sul )hate 10' to Sulphuric acid 1Q 5 to 40 'Amn'i'onium"sulphate-r; 5 to Potassium dichromate A to 10 Cerium sulphate to 10 andupon analysis, it should yield the followlng ingredients and proportlons.

i l 7 Parts by weight Hydrogen 17.00 to 22.00 Oxygen H200 to 221.06 Potassium 4.48 to 29.15 Sulphur' 4.65 to 42.56 Nitrogen; 1.05 to 14.81 Chromium 0 to 3.53 Cerium O to 4.92

It will be understood that a solution analyzing as above maybe compounded otherwise than hereinbefore. set forth, and that therefore the invention is not limited to the stated manner of compounding.

- It will also be understood that although potassium sulphate has been specifically mentioned, another metallic salt of sulphuric acid may be used,-preferably a salt of the same or salt containing chromium may. be used, such as for instance sodium chromate, or else. a

mate, and another salt of cerium withsul- -phuric acid may be substituted for the cerium sulphate mentioned, as long as quantities of chromium andceriuniequivalent to-th'ose mentioned are carried into solution. Therefore it may be broadly stated that not only the substances mentioned but their substitutes or homologues fall within the scope of my invention.

The advantages inherent to an electrolyte of the type specified are a very high conductivity permitting of either reducing the voltage or the time factor, a high amperage ca-.

pacity, that is, a capacity to quickly absorb the oxygen produced at the anode in relatively large volumes per unit of time, a high yield of persulphates, and minimized diffusion losses. I

The latter advantage is due to the fact that the solution has a relatively high coefl'icient of Viscosity. In addition to this, the solution can be prepared-and operated with the greatest ease, the various ingredients being readily miXable with one another, to form a stable and uniform mixture.

I have also found that an electrolyte of the composition stated permits of conducting the electrolytic operation at relatively high temperatures without causing a reduction ofthe persulphate to sulphate. If temperatures higher than 30 to 35 C. are used in connection with electrolytes heretofore in use, a considerable proportion of the persulphate will be reduced to'sulphate so that the yield becomes unsatisfactory.

On the other hand, if a true cyclic process is to be employed throughout the use of relatively high temperatures is desirable in order to prevent crystallization of the persulphate.

My improved electrolyte as stated permits of using temperatures sufficient to prevent the crystallization of the persulphate, and prevents at the same time a diminution of the persulphate yield through reduction.

The solution is practically self sustaining because no losses of active materials occur during the process of distillation; so that the residues of the processes of distillation may be returned over and over again to the electrolytic container or containers, making it necessary only to add water each time the electrolytic process is started.

I claim:

1. An electrolyte for the preparation of an alkali persulphate, comprising, in water solution, sulphuric acid, together with a sulphuric acid salt of an alkali metal, an ammonium salt, cerium, and an alkali metal salt containing chromium.

2. An electrolyte for the preparation of an alkali persulphate, comprising, in water solution, sulphuric acid, together with a sulphuric acid salt of an alkali metal, an ammonium salt, cerium, and an alkali metal salt containing chromium.

3. An electrolyte for the preparation of an alkali persulphate, comprising, in water solution, sulphuric acid, together with sulphuric acid salts of potassium, ammonia and cerium,

and an alkali metal salt containing chromium.

4. An electrolyte for the preparation of an alkali persulphate, comprising, in water solution, sulphuric acid, together with sulphuric acid salts of potassium, ammonia and cerium and a salt of potassium containing chromium.

5. An electrolyte for the preparation of an alkali persulphate, comprising, in water solution, sulphuric acid, together with sulphuric acid salts of an alkali metal, and cerium, ammonium sulphate, and a salt containing chromium.

6. An electrolyte for the preparation of an alkali persulphate, comprising, in water solution, sulphuric acid, together with a sulphuric acid salt of an alkali metal, ammonium sulphate, cerium sulphate, andla salt containing chromium.

7. An electrolyte for the preparation of an alkali persulphate, comprising, in water solution, sulphuric acid, together with sulphuric acid salts of potassium and cerium, ammonium sulphate, and a salt of potassium containing chromium. a

8. An electrolyte for the preparation of an alkali persulphate, comprising, in water solution, sulphuric acid, together with a sulphuric acid salt of potassium, ammonium sulphate, cerium sulphate and a salt of potassium containing chromium.

9. An electrolyte for the preparation of an alkali persulphate, comprising, in water solution, sulphuric acid, together with a sulphuric acid salt of potassium, ammonium sulphate, cerium sulphate, and a salt of potassium containing chromium.

10'. An electrolyte for the preparation of an alkali persulphate analyzing as follows hydrogen, 17.00 to 22.00 parts; oxygen, 142. to 221.06 parts; potassium, 4.48 to 29.15 parts; sulphur, 4.65 to 42.46 parts; nitrogen, from 1.05 to 14.81 parts; chromium, from 0 to 3.53; cerium, from 0 to 4.92 parts, by weight.

11. An electrolyte for the preparation of a compound including in its composition the group S 0 containing cerium.

12. An electrolyte for the preparation of a compound including in its composition the group S 0 containing chromium and a sulphuric acid salt of cerium.

13. An electrolyte for the manufacture of an alkali persulphate, comprising, in water solution, sulphuric acid, together with sulphuric acid salts of an alkali metal, ammonia and cerium, and a salt containing chromium.

14. An electrolyte for the manufacture of an alkali persulphate, comprising, in water solution, sulphuric acid, together with sulphuric acid salts of an alkali metal, ammonia, and cerium, and a potassium salt containing chromium.

ANTON KRATKY. 

